From: Richard Earnshaw <erich@gnu.org>
Date: Fri, 24 Jun 1994 19:35:38 +0000 (+0000)
Subject: (jump_optimize): If we reverse "if (foo) bar else break;" and there follows a NOTE_IN... 
X-Git-Tag: misc/cutover-egcs-0~6386
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f0e1b9a9887363dc693310491da72bd22b061cf4;p=thirdparty%2Fgcc.git

(jump_optimize): If we reverse "if (foo) bar else break;" and there follows a NOTE_INSN_LOOP_END...

(jump_optimize): If we reverse "if (foo) bar else break;"
and there follows a NOTE_INSN_LOOP_END, move the note before "bar".

From-SVN: r7557
---

diff --git a/gcc/jump.c b/gcc/jump.c
index 076f6950b11c..2f9621f47f52 100644
--- a/gcc/jump.c
+++ b/gcc/jump.c
@@ -1750,6 +1750,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 			rtx range2beg = next_active_insn (label1);
 			rtx range1after, range2after;
 			rtx range1before, range2before;
+			rtx rangenext;
 
 			/* Include in each range any notes before it, to be
 			   sure that we get the line number note if any, even
@@ -1783,6 +1784,34 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
 			PREV_INSN (range1beg) = range2before;
 			NEXT_INSN (range1end) = range2after;
 			PREV_INSN (range2after) = range1end;
+
+			/* Check for a loop end note between the end of
+			   range2, and the next code label.  If there is one,
+			   then what we have really seen is
+			   if (foo) break; end_of_loop;
+			   and moved the break sequence outside the loop.
+			   We must move the LOOP_END note to where the
+			   loop really ends now, or we will confuse loop
+			   optimization.  */
+			for (;range2after != label2; range2after = rangenext)
+			  {
+			    rangenext = NEXT_INSN (range2after);
+			    if (GET_CODE (range2after) == NOTE
+				&& (NOTE_LINE_NUMBER (range2after)
+				    == NOTE_INSN_LOOP_END))
+			      {
+				NEXT_INSN (PREV_INSN (range2after))
+				  = rangenext;
+				PREV_INSN (rangenext)
+				  = PREV_INSN (range2after);
+				PREV_INSN (range2after) 
+				  = PREV_INSN (range1beg);
+				NEXT_INSN (range2after) = range1beg;
+				NEXT_INSN (PREV_INSN (range1beg))
+				  = range2after;
+				PREV_INSN (range1beg) = range2after;
+			      }
+			  }
 			changed = 1;
 			continue;
 		      }